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Marshall 5010 Needs Help

Started by El Scorcho, March 18, 2018, 09:32:21 AM

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solidstate2199

Hi
i havent read the whole topic yet but i know the answer to your 5010
"buzzing background" sound...
this is NORMAL behaviour on the 5010.

What you hear is the Ampsound with gain on 10 as a low volume
background noise.
It is a lets call it "design flaw".

The 5010 is only put to good use with the gain on "10" forget it for cleans and
use it like youre supposed to as a "practice 2203" .

I recall that the background fizz at low gain settings is not all that noticable
at higher volumes...so try the Amp with the Master volume turned at least to 6
and forget about playing totally clean gain has to be at 7 for some hendrixy tones.

Good Luck...the 5010 is a good sounding SS Marshall if used properly
for 80s Hardrock played with a higher output Humbucker.

(all IMO)

(a lot of the 5010s have a problem with oscillations at high gain settings,
i have seen so many with this problem that i think its a design flaw too.
Marshall changed a lot of stuff in their solid state amps of the 80s, lots
of revisions.

Enzo

The huge gain problem is less a design flaw than it is people trying to improve the amp.  In that 5000 series of amps, you might see 1458 op amp.  I recommend getting exactly that to replace them.  people "upgrade" to 4558, 4560. 4580, and then their amps become unstable at gain.

Stick with the 1458 there.

Estomagado

Quote from: Enzo on May 02, 2018, 01:02:58 PM
The huge gain problem is less a design flaw than it is people trying to improve the amp.  In that 5000 series of amps, you might see 1458 op amp.  I recommend getting exactly that to replace them.  people "upgrade" to 4558, 4560. 4580, and then their amps become unstable at gain.

Stick with the 1458 there.
1458 is a dual 741. Appaling specs. That's why it works so well with high gain guitar settings. But if you want your amp cleaner, you'd have to upgrade them to 4558s or better, and work on the compensation caps and feedback.

Tubes suck!


El Scorcho

I don't want clean AT ALL on my Marshall, i just want it to sound like a Marshall instead of a cheap practice amp! My old Lead20 sounded great-it just could't be heard over a drummer. It had a sweet sound, wheareas this particular 5010 ( and perhaps the Red McKenzie version in general) sounds like a turd smells. The later versions with the horizontal and single inputs sound really good, and I don't know why mine doesn't- but it really doesn't.

solidstate2199

#64
I had the 5275; Mosfet 100; Lead 12, Artist 3203 , Marshall 5010, Valvestate 100, JCM 900 Dual Reverb...sorry to say this but good Marshall is not happening with any of those...cut the chase and get real.

(1959 2203 2210 JTM45)x(PPIMV and or Attenuator)=ROCK

Could very well be that your 5010 has a transitional circuit from the
earlier Marshall SS Amps, and i can imagine that sounding not pleasant.

The mid 80s 5010 do a generic
ACDC Sound, nothing more or less.

YANSUEMARTINEZ

Quote from: El Scorcho on April 24, 2018, 01:30:07 PM
I'll go back and find that image, jazz bass. In the meantime, I was on the Marshall forum trying to find out anything I could about the JM69 pcb and not having much luck-until I stumbled across a post about a guy with a similar problem to mine, only with his bass amp. The schematic was for his 5503 30 watt bass amp listed a certain pcb, but his had a JM69 board instead, and the components didn't match. So I ran down that schematic, and found it is much more similar to mine. In fact, the transistor values that seemed out of place on the 5010 schematic match. I think the Red McKenzie version of the 5010  is essentially a bass amp.


Excuse me friend, do you know what the value of the VR1, 2, 3, 4, 5 and 6 pots is? I have the same JM 69 board as the one with the red speaker.

YANSUEMARTINEZ

Quote from: El Scorcho on March 21, 2018, 04:09:25 AM
It works-It just has an unpleasant sound. Even on the lower gain input there is a cruddy blanket of harsh fuzz wrapped around what would otherwise be a useable tone. Some of the parts seem a bit 'aftermarket'.


Excuse me friend, do you know what the value of the VR1, 2, 3, 4, 5 and 6 pots is? I have the same JM 69 board as the one with the red speaker.

YANSUEMARTINEZ

Excuse me friends, does anyone know what the value of the VR1, 2, 3, 4, 5 and 6 pots is? I have the same JM 69 board as the one with the red speaker.

Jazz P Bass


dazz

Sorry for the necro post, but I figured out the schematic based on El Scorcho's pics of the pcb, so I thought it might help someone out there at some point. Looks like the circuit is almost the same as the published schematic, but without the bright cap and the presence control was moved back in between the two amplification stages. I used the cap values in the published schematic, not sure about those


El Scorcho

Hey, sorry I haven't been on the forum in awhile, but thanks so much for taking the time and trouble to trace out that schematic! I really appreciate it! I've had to shelve alot of projects since the Covid sitch.
Lately I had the thought of modding the circuit to be more like a  Guv'nor pedal with an led clipping mod, or even dropping in a jfet jcm 800 preamp pcb, although just putting a pedal in front of it would do pretty much the same thing.